Many water sports boards and craft (e.g., surfboards, sailboards, wave skis, etc.) are made of expanded open-cell rigid polymer foam. Where the discussion herein refers to a surfboard or “board”, it applies to surfboards, sailboards, body boards, wave skis, and other types of water sports boards and craft as well. To make a board of open-cell foam, a “molded method” is often used. Specifically, in using the molded method, a mold of the board is filled with liquid foam, which expands to fill the mold. The foam is then allowed to harden in the mold until it is rigid, forming a foam blank. The rigid foam is made of air cells that are open to each other. The cells at the surface of the rigid foam are also open to the atmosphere. Another method of board formation is the traditional hand-shaping method wherein the board is cut, or shaped, from a block of expanded foam to form the foam blank. To protect the foam blank from deterioration, a sealing layer is applied to the surface to protect the foam blank from the elements. The sealing layer is often made with materials such as fiberglass cloth and epoxy resins.
A problem with surfboards made with foam blanks with a sealing layer is the possibility of delamination, where the sealing layer separates from the foam blank. The repeated use of a surfboard may cause an indentation where a user places their feet, which may separate the sealing layer from the foam. Further, excessive heat will cause trapped gasses in the interior of the surfboard to expand separating the sealing layer from the foam blank and creating bubbles in the surfboard. Additionally, the inadvertent application of a large force, such as dropping the board on a hard floor or hitting the edge of the board on a rock, will damage the sealing layer and separate it from the foam. If the initial stages of delamination are not addressed, the small local areas of delamination can grow into larger delaminated areas thereby compromising the integrity of the surfboard.
Unfortunately, even though covered with a sealing layer, in the event the board is delaminated and the sealing layer is breached, the board may absorb water through that breach. When the open-cell foam has absorbed water, the open-cell foam is much heavier than when it is dry. A board made with open-cell foam that has absorbed water is significantly more difficult to use because of its increased weight and decreased buoyancy. Furthermore, a board that has absorbed water must be dried out before it is stored, in order to avoid deterioration of the board. Additionally, as trapped water and gases expand due to heat, the increased volume created by the expansion of the water and gas will cause the sealing layer to further delaminate from the foam.
In light of the above, it would be advantageous to make a board with the ability to prevent the delamination of the sealing layer of a surfboard. It would further be advantageous to make a board having similar buoyancy, rigidity, and durability characteristics of a board made from open-cell foam, yet does not absorb water into the foam material if the waterproofing material is breached.